1. Field of the Invention
The present invention relates to a shutter opening device for opening a shutter of a cartridge, and more particularly to a shutter opening device which is suitable for use in a magneto-optical disk drive.
2. Related Background Art
FIG. 1 shows a conventional cartridge of a magneto-optical disk. In the figure, numeral 1 denotes a disk-shaped recording medium, and numeral 2 denotes a cartridge for accommodating the medium. A shutter 3 is slidably supported in a direction A. The shutter 3 is imparted with a restoring force by a spring 5. In a non-use mode of the cartridge, the shutter is kept closed to prevent foreign materials such as dust from entering. FIG. 2 shows an open position of the shutter of the cartridge of FIG. 1. An engagement member 6 for transmitting a shutter open/close force to the shutter 3 is fixed so that the shutter is opened by pushing a side 7 of the engagement member 6.
A shutter opening device for such a cartridge of the magneto-optical disk as shown in FIG. 3 has been known in the art.
An operation of the shutter opening device shown in FIG. 3 is explained below. When the cartridge 2 is inserted toward a direction B which is a drive direction, an open/close member 8 engages with the side 7 of the engagement member 6 so that the engagement member 6 is slid in the direction A. In order to attain the sliding, pins 9 and 10 are provided under the open/close member 8. The pins 9 and 10 are guided by guide grooves 12 and 13, respectively, formed in a guide plate 11, and as the cartridge 2 moves in the direction B, the engagement member 6 receives a force on the side 7 thereof so that the shutter is opened.
Anti-escape members 14 and 15 are fitted to the pins 9 and 10 to prevent the pins 9 and 10 from moving away from the guide grooves, and one end of a spring 16 is fixed to the pin 9 and the other end thereof is fixed to the guide plate 11 so that the open/close member 8 is restored to the original position when the cartridge is removed.
Numeral 17 denotes a turn table for rotating the disk-shaped recording medium 1, numeral 18 denotes an optical pickup, and numeral 19 denotes a magnetic field application device provided on the guide plate 11.
In the above prior art device, however, since the shutter 3 is not completely opened until the movement of the cartridge 2 in the direction B essentially terminates, it is necessary to retract the magnetic field application device 19 (which is positioned in the vicinity of the recording medium with a smaller spacing thereto than an interval between the recording medium and the shutter in order to converge the magnetic field to the recording medium when performing recording, reproducing and erasing operations) upward until the loading of the cartridge 2 is completed in order to avoid an interference between the magnetic field application device 19 and the shutter 3. To this end, a retraction mechanism and a space therefor are required, which results in an increase of size and weight, a reduction of a response speed and a increase in cost.
In light of the above, a shutter open/close device of a cartridge which permits the loading of the cartridge 2 while the magnetic field application device 19 is stationary, that is, which creates no interference between the magnetic field application device and the shutter has been sought.